In a large skillet, heat oil over medium heat.
Cook onion, peppers and garlic, stirring occasionally, until soft.
Add remaining ingredients, stir well, and reduce heat.
Simmer 20-30 minutes (not necessary if you don't have the time, but
good for blending the flavors & softening the beans.)
Adjust seasonings to taste.
Serve hot over cooked rice, or stuff into taco shells or tortillas.

Feel free to substitute seasonings according to your tastes.
You can even just dump a packet of chili or taco seasoning mix in
if you like.